Last updated: 16 September 2026
Quick answer. Incoming inspection protects the order you placed; outgoing inspection protects the order you ship. Agree in writing what will be inspected, against which drawing revision, by whom and by what acceptance rule. Use first-article approval before the batch runs, and confirm the specific sampling plan with your inspection provider — this page publishes no AQL table.
Editorial position: China Custom Parts is an independent sourcing knowledge site — not a factory, not a marketplace, not a directory. This page publishes no supplier list and no sampling table. It gives you the method, the documents and the wording to agree with your own inspection provider.
Quality control on an import order means two moments, and they fail in different ways. Incoming inspection catches the wrong grade, the wrong finish, the wrong revision, damaged stock and certificates that do not match the material on the rack. Outgoing or pre-shipment inspection catches what the process did: dimensions off the drawing, plating defects, missing hardware in the pack, wrong carton marks, wrong quantity.
| Inspection point | What it is for | What it typically misses |
|---|---|---|
| Incoming material and components | Verifying grade, condition, traceability and certificate-to-material match before value is added | Process capability — it says nothing about the operations still to come |
| In-process, at the operation that creates a critical feature | Catching a drifting process while the lot is still salvageable, and testing the first-piece approval | Defects created downstream, and mixed material already consumed |
| Final or pre-shipment, before packing and dispatch | Verifying the delivered configuration against the drawing and the order: dimensions, finish, function, markings, packaging, quantity | Causes — it finds the symptom, so a root-cause step is still needed |
Two consequences follow: an inspection sorts what you have already bought, it does not explain why the process drifted; and the inspection point you choose determines what is left to detect. Decide which characteristics are critical, major and minor before you order — that drives the inspection point, the sample and the disposition.
Acceptance sampling is a decision rule for finite lots: you take a defined sample from a defined lot, count the nonconforming units or defects, and compare the count against an acceptance rule. The plans that define how many units to inspect and how many failures to allow are published in national and international sampling standards for inspection by attributes. This page reproduces none of those tables, and a table taken from a website is not evidence: obtain the current edition from the standards body, or have your inspection provider state the plan it will use, and confirm the specific sampling plan with your inspection provider before the order runs. Write it onto the purchase order.
Sampling fits homogeneous lots, produced by the same process, in the same period, with the same material, and characteristics you can judge by attributes or measure cheaply and non-destructively. It does not fit the following, and you should not let it be used:
Sampling cannot fix a silent drawing: if a feature is not toleranced, no plan will tell you whether it is acceptable.
First-article inspection is the full verification of a part produced with the final production process, tooling, programme and fixtures, against every characteristic on the drawing. Where sampling asks how many units of a lot are acceptable, first-article inspection asks whether the process produces the part the drawing describes. It belongs before the batch runs.
Run first-article approval when any of the following changes, and record the reason each time:
A usable first-article report documents the whole layout, not a summary: the part number and drawing revision; every characteristic with nominal, tolerance, actual value, method and pass or fail; the material grade and the certificate for the lot consumed; the finish verification; sample identification; the disposition of any out-of-tolerance result, including a written deviation if you accept it; and the approver's signature. When the report is accepted, seal a golden sample and write the approval reference into the inspection instruction, so later lots are compared against an approved reference rather than a memory.
Two disciplines matter more than the form. If a fit dimension is toleranced on your drawing, it must appear in the report as a measured value, not as "OK". And deviations must be approved by you in writing: a supplier that self-approves an out-of-tolerance first article has told you that the drawing is advisory — a finding about the relationship, not the part.
A management-system certificate is not a substitute for this. ISO states that it does not perform certification or issue certificates, and the current edition of the quality management standard replaced the 2015 edition. Ask which edition a certificate names, and validate it in the issuing database rather than trusting the file.
An inspection report is evidence only if it is tied to your order and reproducible. Specify in the purchase order:
A material certificate answers a different question: what the material was declared to be. Make sure it identifies the heat or lot number actually consumed for your order, not a general mill certificate for the grade, and that it gives the chemical composition and mechanical properties the grade requires. Then require traceability from the delivered parts back to that number: a certificate that cannot be connected to the material you received is a filing, not evidence.
Where an outside laboratory measures dimensions or performance, ask for a report from a laboratory meeting ISO/IEC 17025, the international standard for the competence, impartiality and consistent operation of testing and calibration laboratories, used by accreditation bodies as the criterion for accrediting them. The report should name the method and should not leave you guessing whether the laboratory was accredited for that test.
For hardware sourced against a standard, remember that the standard defines the property class, dimensions, tolerances and test methods, and that a claim of conformity has to name the standard. Fastener standards for door, window and cabinet hardware sit with ASTM Committee F16 on Fasteners. When a supplier claims a standard, obtain it and check the claimed values against your inspection results.
When inspection finds nonconformity, the decision about what happens next is yours, not the supplier's. The standard set of dispositions is small, and each one has a written form:
| Disposition | What it means in practice | What you must obtain |
|---|---|---|
| Rework | The supplier brings the units into conformity with the original specification | A re-inspection of the reworked units, and a record of the operation |
| Repair with approval | The supplier restores function by a method that departs from the drawing | Your written approval of the method, and a re-test of the affected characteristic |
| Use as is (concession) | You accept the nonconforming units without change | Your written deviation, traceable to the lot, with a record of who accepted what |
| Re-grade or alternate use | The units are diverted to a different, less demanding application | Your written agreement and unambiguous marking, so the units cannot ship into the original order |
| Return or replace | The lot goes back and is remade | Shipping and traceability records, and a replacement inspection |
| Scrap | The units are destroyed | Evidence of destruction, so the lot cannot reappear in a later shipment |
Keep the physical control equal to the paperwork. Nonconforming units must be quarantined, identified by status and separated from conforming stock; the commonest failure is not a wrong decision but a correct decision lost in a mixed warehouse. Then close the cause: require root-cause analysis, an action that addresses the cause rather than the symptom, and verification that it worked, confirmed on subsequent lots. A returned corrective-action form is a statement of intent; a verified result is evidence. If the same characteristic fails again, treat it as a system finding and escalate.
Almost every inspection dispute is a specification dispute. Settle the following in writing before production starts, in the purchase order or an attached quality agreement:
Send the same criteria to every candidate supplier, so that the answers compare. Suppliers who question a tolerance you cannot measure, or propose a different inspection point, are generally the ones who can control the process.
Send us the requirement rather than a finished specification. We will tell you what the drawing still needs to specify, which characteristics to classify as critical, and which inspection steps to agree in writing before a supplier starts quoting.
Request a quote → Attach the drawing, state material and finishing requirements, and describe how the part is used and where it will be sold.
Last updated: 16 September 2026.
No. Acceptance sampling assumes a homogeneous lot, a defined unit of product and a plan agreed in advance. It is unsuitable for destructive tests, for very small lots that are cheaper to check fully, for a single critical or safety-related characteristic, and for conformity that depends on traceability of material rather than on counting units. This site publishes no sampling table; obtain the current edition from the standards body, and confirm the specific sampling plan with your inspection provider.
A first-article report documents a part made with the final process, tooling and programme: the part number and drawing revision; every characteristic with nominal, tolerance, actual value, method and pass or fail; the material grade and the certificate for the lot consumed; the finish verification; sample identification; the disposition of any out-of-tolerance result with a written deviation; and the approver's signature. Keep a sealed golden sample and reference the approval in later inspection instructions.
Quarantine and identify it by status so it cannot mix with conforming stock, then choose a written disposition: rework, repair with your approval, use as is with a documented deviation, re-grade for another use, return, or scrap with evidence of destruction. For significant nonconformities, require root-cause analysis and verify the corrective action on subsequent lots. A returned corrective-action form is a statement of intent, not evidence.
All sources retrieved 16 September 2026. This page is an independent reading of the sources listed; the standards and official pages themselves are the specification.
| Fact used on this page | Source |
|---|---|
| S1 | ISO/IEC https://www.iso.org/standard/66912.html |
| S2 | ISO https://www.iso.org/certification.html |
| S3 | ISO https://www.iso.org/standard/62085.html |
| S4 | IAF CertSearch https://www.iafcertsearch.org/ |
| S5 | ASTM International https://www.astm.org/membership-participation/technical-committees/committee-f16 |
| S6 | ISO ｜ ANSI / ASQ https://www.iso.org/standards.html ｜ https://webstore.ansi.org/ |
Independent resource. This page is published by an independent information resource. It is not a factory, broker or marketplace, and no prices, minimum order quantities, lead times or supplier lists are published. Where a figure or a requirement depends on a standard or an official rule, the standard or the official page is the specification — verify the current edition before you commit to a purchase decision. Sources used for this page are listed below and were retrieved on 16 September 2026.